PO404 & PO405 Dodge EGR Codes

Just a short funny one, because I mentioned my devouring of tech data, especially stuff on every day glitches happening to our modern chariots. Earlier today I had a contractor pull in the shop with his 2005 Dodge Ram 1500. He got out and met me in front of his truck. I’ll tag him as Dan Dodge for the blog. Medium height, flushed of face, and carrying around thirty extra pounds, Dan was wearing one of those worried ‘I know I’m going to get ripped off’ looks. He confirmed it shortly after my usual customer greeting.

“Listen. I know you don’t work for free, but I just need to get your opinion. I can’t afford anymore shit happening with this truck.”

“Well, you’re right about one thing I don’t work for free, but tell me what kind of trouble you’re having with the truck. I don’t charge for listening.”

Dan chuckled a little at that one. “Okay… I went to the Autozone over on McArthur and got the codes read there because my check engine light was on.”

He took a piece of notebook paper out to look at. “They said I had codes PO404 and PO405… something to do with the EGR (Exhaust Gas Recirculation) valve position and voltage.”

Okay so far, but thanks to an active imagination and extensive tech reading, my mind has already jumped to the plot climax. “You replaced the EGR valve, and you still have a PO405 Code.”

Dan’s face looks like, and here’s an obscure comparison, the Replicant at the beginning of Blade Runner, when he’s asked questions by a government agent trying to pick out the escaped Replicants, ‘there’s a turtle on its back in the desert and you’re not helping’. I love this part. Dan goes away for a moment.

“How… how could you know that?”

Because I’m the great and all powerful Oz… naaahhh… I read a case history while doing my every day tech troubleshooting, service bulletins, and recall announcements. “I keep up on this stuff. First, did you put an Autozone EGR on it or an OEM one?”

“They didn’t have one so I had to go to the dealer in Walnut Creek.”

“Outstanding. Here’s what we’ll have to do. We need to disconnect your battery cables and touch them together. Then we wait a half hour. Then we reconnect the terminals and you’ll be all set. You may have a few drivability issues though while the on board computer relearns the driving parameters though, but that should be minor for a couple days. I also have to warn you sometimes you have to have a reflash done on the computer too if this doesn’t work.”

“Why do I need to do this again?” Dan is still stuck on my out of the blue right on guess.

“It’s like this. Your EGR valve was bad, but after you replaced it, the computer still thinks you have an old bad one. It’s just like Windows on your computer when you get the blue screen of death. You need to reboot. Want to try it?”

“Sure.”

I disconnect the battery, touch the terminals together for thirty seconds, and then we left it alone. Dan sat in my office and I finished up a brake job on an 06 Saturn I was working on. I then reconnected the battery and sent Dan on his way. Since Dan had already told me the check engine light came back on only minutes into the driving cycle after replacing the EGR, I told him to drive it for the day and give me a call as to how it worked out. Dan just called and said everything was working perfectly. I needed to experiment, and Dan needed to be the guinea pig. Now that the great and all knowing Oz has worked a minor miracle, we’ll see if Dan comes in for servicing or if he tries to get the all powerful Oz to work for free again. That would be… NO.  :)